Synchronized centrifugal pawl clutch



Qct. 14, 1952 E. R. MAURER 2,613,783

SYNGHRONIZED CENTRIUGAL PAWL CLUTCH Original-Filed Feb. 19, 1945l 3Sheets-Shet l I )a Il I /j y Z I| K E? /4 A( g ,2f

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Od. 14, 1952 E. R. MAURE'R sYNcHRoNIzED CIENTRIFUGAL Pm. QLU'LCHoriginal Filed Feb. 19. 1945 Oct. 1.4, 1952 E. R. MAURER 2,613,783

sYNcHRoNIzED CENTRIFUGAL PAWL CLUTCH originaLFiled Feb. 19,4.,1945 ssheets-sheet s INVENToR. JJu/zz j? /Vdlrez Patented Oct. T4, 1952.sYNoHRoNIzED CENTRIEUGAL PAWL CLUTCH Edwin Maurer, Detroit, Mich.,assigner to Chrysler Corporation, Highland Park, Mich., a corporation ofDelaware original application February 19, 1945, seriaiNo.

578,631. Divided and this application July 2d,y 1948, Serial No. 40,568

This invention relates -to -power `transmitting drives providing a pawlclutch of the centrifugal type engageable to drivingly connect a drivingand a driven member. More particularly my inven- -tion has reference tocentrifugal pawl clutch mechanism providing means for controlling thepawl engagement, for example, whereby it may be made operably responsiveto certain predetermined conditions of operation of the drive structurewith which the' clutch mechanism is associated. The present applicationis a division of my copending application Serial' No. 578,631 filedFebruary 19, 1945, now Patent No. 2,448,539.

My invention will be illustrated as applied to a centrifugally actuatedpawl clutch'mechanism 'for locking together against slip under certainconditions of vehicle operation a pair of fluid power transmittingelements, which clutch mechanism includes a driving member drivinglyassociated with one of said power transmitting elements, a driven memberdrivingly associated with the other of the power transmitting elements,a locking pawl carried by one of the members and operably responsive tocentrifugal force upon predetermined rotation of said one member forinterconnecting said clutch elements and means for preventing theoperation of the clutch mechanism for positively locking together thefluid Apower transmitting elements until the rotative Yspeeds of theclutch members have been rst `brought to approximate synchrOnism.

An object of the invention therefore, is to pro? `vide an automaticallyoperable clutch mechanism with means operable in response to functioningof the power transmitting drive structure in which the clutch mechanismis incorporated for controlling engagement of the clutch mechanism.

Another object is to provide a centrifugal type pawl clutch mechanismfor an automotive vehicle drive structure with blocker means operableautomatically under certain conditions of vehicle functioning forpositively preventing engagement of the pawl.

A more particular object is the provision of control ,means aforesaid inthe nature of a frictionally driven balk ring provided with a pair ofcircumferentially spaced fingers for interlocking with .the pawl memberunder certain conditions of operation to prevent engagement with itspawl receiving shell, one finger providing the locking function underdrive conditions, the other under -coast conditions of operation.

Other objects of my invention will be apparent .from the lfollowingdescription and the drawings wherein:

8 Claims. (Cl. 2192-105) .2 Fig. 1 is a sectional elevationof ia portion4of ra transmission embodying ,the present invention;

Fig. `2 is a .sectional viewtak'en along `the line 2-2ofFig.1; I v

Fig. .3 Ais van elevational view of the control ring of my vinventionshown 'in perspective; .y

Figs. 4 and '5 are viewssimilar to those .ofFigs. l and 2 of amodifledziorm of the invention;

Figure 6 is a sectional view similar toxthatoi Figure 2 omitting thepawl balking member; and l Figure '7 is a perspective view of one :ofthe pawls of Figure 6. f

"Referring to Figsfl ffto '5, it will be seen that there is illustrateda fluid power transmitting' device such as a iiuid coupling having animpeller lil carried Vby a hub ll which is fastened to an enginecrankshaft ki2 'by means offs'tuds 13|A and nuts i4. The impellerincludes ahousingportion lil which encloses a `runner l5,the-latterf'b'eing welded or otherwise fastened to a hub IIB. A forwardseal Il and a rear seal I8 prevent leakage of the fluid whichis'circulated in the passages formed by the vanes lil, as isconventional inthe art. The runner hub' i6 has a tubular po'rtionas fat2i? by which drive is 'imparted toA ther input "member of the vehicletransmission. This tubuplate orr member 2d which has an innerAcylindrical surface 2Min engagement with the .rollers 23 and carries apair of centrifugally actuated palwls 25. The pawls are an element o fa,centrifugal clutch and have ears 26 for loosely engaging .bolts 2l. Thebolts 21 are rigidly .carriedin the pawl drive plate 2li, as shown, andmount a c oil compression spring 28 which tends to keep the ,pawls 25 inretracted, that is, disengaged position. AThe pawls are shaped asillustrated and each has an integral tail vportion 29 which liesalongside the engaging or head portion v3Ilfof the other pawl and acts-as aA dragging connection between the pawl and the plate 24 .as well asa guide to keep the pawls in position. The pawlsoperate in a slidewayY3| formed by the rearwardly projecting annular segmentsZ, 33 of the.pawl drive plate .2.4. It will b e understood that .thepawlslooselyvernbrace the drive plate Mandhavesumcient clearance withrespect thereto such .that .theycanmove radially outwardly under theinfluence :of centrifugal force. -Elfhis .movement ,is limited in :both

as follows.

directions by engagement of the inner surface of the pawls with the hubportion I6 as will be understcod.

The springs 28 may be of any desired strength to produce the-operatingcharacteristics desired, it being understood that the springs will keepthe pawls in the illustrated retracted position until a. predeterminedspeed of the shaft I2 is reached, whereupon the centrifugal force willovercome the force of the springs and the pawls will tend to moveradially outwardly as will be explained below.

The runner hub I 6 has a slight baiile 34 for reducing the efficiency ofthe coupling at idling speed and for preventing surges and is alsoformed with a forwardly projecting annular portion 35 provided withcircumferentially spaced pawl receiving openings or notches 36. Fournotches are shown but more may be required in some installations just asmore than two pawls may be recuired for smooth operation. Y

The notches 36 are shown radially aligned with the pawls 25 such thatthe pawls may engage the notches to lock the drive plate 24 to therunner hub I6. The pawls 25 are formed with an outer cammed surface 31which is shaped such that when the pawls are urged outwardly bycentrifugal force and the notched member 35 of the runner I 6 is rotatedat a different speed than the plate 24, the surface 3'! will engage theedge 38 of the notches 36 and cam the pawls inwardly until the speeds ofthe two members are substantiallv equal whereupon the pawls will enterthe notches.

Each of the .pawls is provided with three detent holes 39 which areadapted .to receive a spring urged ball detent 40 carried by the driveplate 24. The detents prevent hunting of the pawls and tend to hold thepawls in one of three positions while the plate 24 is rotating withinthe respective desired speed ranges.

Each pawl is provided with an inner tooth 4I which is adapted to engageopenings. slots or recesses 42 formed in the runner hub I6 and similaropenings 43 in the portion 22 of the impeller hub II. The inner teeth 4Iof the pawls are preferablv of stepped construction so that upon inwardradial movement thereof the slots 42 in the runner hub will be engagedprior to the slots 43 in the annular portion 22 of the impeller hub II.

Otherwise, there might be instances when the .teeth 4I would not engageboth the runner and impeller hubs as `soon vas desired because therunner and engine might not come to rest at the same time and with, theslots 42, 43 align axially. The stepped teeth 4I facilitate theclutching action but the teeth may be made without the step if desired.The teeth 4I are cammed so that theyl will smoothlv engage theresnective openings 42, 43 when the pawls are rotating in synchronismwith the runner hub I6 and the impeller hub I I or both as the case maybe. Should the pawls 25 be urged outwardly by centrifugal force orinwardly bythe springs 28 at times when the parts to be engaged are notrotating synchronously, the cammed outer ends of the pawls will engagethe edges of the respective openings and the pawls will be preventedfrom engaging the openings until the pawls reach synchronism.

The operation Aof the device so far described is Let it be assumed thatthe parts are in the position illustrated with the vehicle engine, thehub I6, `and the shaft 2I at rest. The engine may be started by pushingor towing the car and thev engine compression may be used for braking ongrades by coasting with a dead en- 4 gine under these conditions becausethe impeller and runner are directly connected through the pawl teeth4I.

When the engine is started the pawls 25 will disengage themselves fromthe hub portions I6 and 22 at approximately 325 R. P. M. The retractingsprings 28 and the detent springs 44are preferably chosen such thatcentrifugal force on the pawls will effect their outward movement to midposition at an engine speed of between 250 and 400 R. P. M., the engineidling speed with a warm engine being about 425 R. P. M. It is assumedthat a vehicle clutch (not shown) or other equivalent disengaging meanslocated between the runner I5 and the drive wheels will be disengagedwhen the engine is started or the transmission is in neutral. In suchcase, the frictional load on the pawl teeth 4I will not be great'and thepawls will disengage without difflculty.

When the pawls have moved to mid position the detent ball 40 engages thecenter hole 39 in the pawl 25 and the impeller I0 and runner I5 are freefor normal operation. The vehicle may then be started, accelerated,maneuvered, etc., with the coupling elements slipping relative to eachother.

When the vehicle has been accelerated to the predetermined cruisingspeed, for example, about 25 M. P. H. the pawls 25 under the influenceof centrifugal force, tend to move outwardly to engage the openings 36.They will be prevented from engaging the openings, however, so long asthe speeds of the pawls and the hub I6 are different as they normallywill be because of the slip in the coupling. The driver can effectengagement of the pawls by momentarily releasing the throttle whereuponthe impeller will drop in speed relative to the runner and the pawlswill engage at the instant of-synchronism.

From the description it will be apparent that the pawls acting under theiniiuence of centrifugal force when the engine is accelerated, willovercome the ball detent 40 and become disengaged from the openings 42,43. As the speed of the engine is increased the pawls continue theiroutward movement for engagement with the notches 36 of the hub I6.

As a means to positively block the movement of the pawls from midposition under asynchronous conditions, I provide a blocking or balkingmember in the form of an open ring 45 carried by an annular fiange 4'6on the hub I6 in frictional drive relationship therewith. The ring 45has opposite pairs of outwardly projecting legs 41, 43 and 49, 5Urespectively, the former forming extensions of the free ends of thering. The leg portions give the ring the general appearance of a doubleended yoke. The leg portions 41, v49 are provided with circumferentialprojections 5I and the leg portions 48, 50 with projections 52. Theprojections 5I, 52 are adapted to be received in the opposite endsrespectively of circumferential openings or slots 53 in the pawls 25when the pawls are moved radially outward a distance to causedisengagement of the inner teeth 4I from the openings 42 and 43. Thisdisengagementof the teeth 4I permits relative rotation between theimpeller I0 and the runner I5 known as slippage thereby causing thediametrically opposite projections 52 to interlock with the ends of theslots 48 and block further outward movement oftarilylwliichfcausesadropinspeed of 'theiimpeller I Il 'and yof thedrive plate '124 relative tothe runner hub I 6 which car-ries theslotted integral fannular portion '35. When the speed of Vthe 'impellerand its 'associated part drops to the speed of the runner IfB, thefrictional Vcontact between the 'latter and the balk ring 45 willeff-ect slight yrotation of the ring in the-direction of rotationtherebywithdrawing the projections 52 Ifror'nthe openings. and permitting thepawls 'to 'move outwardly `by the action of centrifugal -force 'intolengagement with the notches '35 before"theprojections 5I can effectengagement with the pawls the projections 5I,`52 being spacedsuiliciently for this ypurpose andthe speeds `.of the impeller andrunnerlbeing in Isynchronisrn at this instant as above described.

The firripellerand runner are i-now 'locked for conjointoperationjwithout 'slippage so long as the irripeller tends'to overrunthe runner asis the case duringnormal driving of vthefcar "bytheengine.- When the car tends" to drive 'the engine above the aforesaidpawlcut in speed, the runner lI 5 will loverrun the impeller "I l! andthere will be slippage therebetween due 'to the roller :clutch "23 whichacts yas 'a one-way driving connection "be-k tween fthe impeller and thepawl 'drive` .plate 24. When the vehicle speed 'is reduced, vthe ,pawls25 -will drop out A'of the openings 3B at some speed below 25 'M. P.depending upon the lstrength y of the detentsprings =44 and thefrictional'load on fthe vpa-wls 'which will be 'less when "the vehicleis coasting than when the'engineis driving due Ito the roller clutchv`The runner I5 and the ring 45 through its frictional drive connectionare now rotating at a greater speed than the impeller I Il therebycausing the projections 5I' to engage the openings 53 as the vpawls areAmoved inwardly. This engagement holds the pawls yagainst further inwardmovement preventing the teeth 4I from entering 'the openings 42, 43 thuspreventing a positive lookup between the impeller and the lrunner.Thiscondition continues solongas the runner .overruns .the .impellen"When :the yehicle Ahas stopped and the engine is idling, "thebalkingring 45 .continues to `rotate in a counterclockwise direction (asviewed in'Fig. T2) under drive by the pawls 25 the frictional drag ofthe hub portion i5 on the ring eiecting disengagement of the projections5I from the openings 53 and engaging the projections 52 therein. Whenthe engine has stopped the projections 52 may continue in the openings53 and the pawls 25 rep main locked against inward movement forengagement of the teeth 4I with the slots 42 butv as soon as there isany relative movement between the hubs I l and I6 as would be the casein towing or pushing the vehicle with the engine stopped, the balk ring45 would by its frictional engagement with the hub I6 be movedcounterclockwise thereby disengaging the projections 52 from openings 53to permit the pawls to move inwardly locking the teeth 4I in theopenings 42 and 43. The impeller I and runner I5 are then directlylocked so that the engine may be started by towing or pushing thevehicle.

The form of the device illustrated in Figs. 4 and embodies the sameconstruction as illustrated in Figs. 1 and 2 except that the overrunningrollers 2,3, lookup teeth 4I, and spring-pressed ball 4!) have beenomitted and the pawls are driven directly with the impeller hub becauseof the lookup between the pawl plate 24 and impeller hub l I effected bythe pins 55. The operation of the pawls 25 and balk ring 38 are the samebut there is no freewheeling when the pawls objects `of the invention,it1 will :be 'understood that various .,modifications, :changes and`substitutions Amay tbe madgewithoutdeparting rom the spirit thereof,:for example, various changes :may be :made :inthe size, shap,e,:,andarrangement .of the parts by l.thosetskilledin-:the art. EThze'presentinvention fis, therefore, to kbe construed `to include allsuc'hfmodiiicati-ons, ichanges and substitutions.

I claim.: f

l. A vpower transmitting 4`clutch mechanism comprising a driving member,a driven member,-

a 4centrifugally responsive pawl vcarriedby one of said members,`radially aligned openings :said other `Imember-*for .receiving said`pawl at sa relatively rslow and a relativelyl :East rotative speedrespectively of said onegmember'andzsubstantially synchronous :rotationof said fmembers, :and ,rotatable 'means `in irictional Adrivingconnection with :said othermemberfmovable into blockinggrelationshiprelative to said pawl-:at predetermined rotative speed of l said ionemember intermediate said slow and 'fast `'speeds ifor preventingengagement or said `pawl 'at :said .fast 'speed `.ofxsaid one memberduring :asynchronous :rotation of :saidmembers. l v

2. A power transmita' l@ :clutchmechamsmcomprising ta driving zmember; acentriugally responsive Ypawl carried by ,said-drivingimember, said pawlhaving a `#head :including .a body portion :and a `clutching tip, anannular 'portionqon said driven member surrounding saidpawl, an

vopening zin said annular portion adapted :.to -receivesaid pawl 'tipatpredetermined `speed .of :said

driving .member kand substantially "synchronous rotation of said membersior establishing apositive drive between said members, an open ringfrictionally journalled on said driven member within said annularportion, the open ends of said ring being formed with outwardlyextending leg portions, lateral projections on said leg portions in theplane thereof and a recess in said body portion of said pawl head forreceiving said lateral projections for preventing engagement oi saidpawl with said opening during asynchronous rotation of said members,said lateral projections being spaced apart sufciently to provide lostmotion between said pawl and said ring. l

3. A power transmitting clutch mechanism comprising a rotatable pawlcarrying core, a rotatable shell member having a pawl receiving recesstherein, a pawl carried by said core and movably responsive tocentrifugal force upon rotation of said core to engage said recess forestablishinging a positive drive between said core and shell andmeansfor preventing engagement of said pawl during asynchronous rotation ofsaid core and shell comprising an open ring having frictional driveconnection with said shell member, an outwardly extending finger on oneopen end of said ring, a circumferentially directed projection on saidringer and a circumferentially directed slot in said pawl for engageablyreceiving said projection, the ends of said ring being spaced apartsufciently to permit relative oscillation between'said pawl andprojection before the latter enters into engagement with said slot andwhile the pawl is unrestrained by said ring.

4. A power transmitting clutch mechanism comprising a driving member, adriven member, a centrifugally responsive pawl carried by one of saidmembers, said pawl having a head including a body portion and aclutching tip; a recess on said other member for receiving said pawl tipat predetermined speed and substantially synchronous rotation of saidmembers to establish a positive drive between said members, a slot inthe body of said pawl head and a rotatable open ring in constantfrictional drive relationship with said other member, said ring having apair of adjacent leg portions spaced apart a distance greater than thewidth of the pawl head body portion in the plane of said ring and saidleg portions being provided with tooth-like projections engageable insaid slot for preventing engagement of said pawl with said other memberduring asynchronous rotation of said members.

l. 5. 'A power transmitting clutch mechanism as claimed in claim 4wherein the adjacent leg portions form continuations of the open ends ofthe ring and wherein said projections are lateral projections of the legportions.

6. vA power transmitting clutch mechanism as claimed in claim 4 whereinsaid ring has a second pair"of leg portions diametrically opposite therst mentioned pair.

' 7. A power transmitting clutch mechanism comprising'a driving member,a driven member, a centrifugally responsive pawl carriedy by saiddriving member, said pawl having a head including a body portion and aclutching tip, an annular portion on said driven member, an opening insaid 'annular portion engageable by said pawl tip at predetermined speedof vsaid driving member and substantially synchronous rotation of saidmembers for establishing a positive drive between said members, a pawlbalking member having an annular-like portion in constant frictionaldrive connectionwith said driven member and having a pair ofspaced-apart leg portions extending outwardly away from said annularportion of said balking member, said pawl body portion and each of saidleg portions having cooperable interengageable tooth and slot portionsinterengageable for preventing engagement of said pawl tip with saidopening during asynchronous rotation of said members, said leg portionsbeing spaced apart suiiiciently to permit lost motion between said 'pawland balking member before either cooperable tooth and slot portions mayenter into interengagement and while the other cooperable tooth and slotportions are still disengaged.

8. A power ltransmitting clutch mechanism comprising a driving member, adriven member, a centrifugally responsive pawl carried by said drivingmember, said pawl having a head including a body portion and a clutchingtip, anannular portion on said driven member surrounding said pawl, anopening in said annular portion adapted to receive said pawl tip atpredetermined speed of said driving member and substantially synchronousrotation ofsaid members for establishing a positive drive between saidmembers, a ring having a portion frictionally journalled on said drivenmember within said annular portion, and having adjacent leg portionsextending outwardly away from said journall'ed portion, said legportions including tooth-like elements adapted for interengagement withsaid body portion of said pawl head for preventing engagement of saidpawl tip with said opening during asynchronous rotation of saidmember,said elements being spaced apart sufciently to provide lost motionbetween said pawl and said ring.

EDWIN R. MAURER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED lSTATES PATENTS Number Name Date 2,179,927 Fishburn Nov. 14, 19392,194,787 Dunn Mar. 26, 1940 2,210,668 Hopkins Aug. 6, 1940 2,278,623Orr Apr. 7, 1942 2,448,539 Maurer Sept. 7, 1948

